8. Colors -> Brightness-Contrast, you may customise it as you wish, here Brightness -30, Contrast 40

And yep, that's all. As in the case of this tutorial Moddb.com this texture is a bit repetitive and generic as well as somewhat blurred, that's why it always comes in handy to customise effects and change this rigified procedure of creating grass textures in such a way so as to suit your own needs (you need to 'mod' tutorial steps a bit and see how it works out).